linux-kernel - Re: [PATCH] perf sched: Fix sched latency analysis incorrect

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Date:   Fri, 3 Mar 2023 18:14:03 -0800
From:   Namhyung Kim <namhyung@...nel.org>
To:     Chunxin Zang <zangchunxin@...iang.com>
Cc:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...nel.org, irogers@...gle.com,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jerry Zhou <zhouchunhua@...iang.com>
Subject: Re: [PATCH] perf sched: Fix sched latency analysis incorrect

Hello,

On Fri, Mar 3, 2023 at 3:53 AM Chunxin Zang <zangchunxin@...iang.com> wrote:
>
> 'perf sched latency' is incorrect to get process schedule latency
> when it used 'sched:sched_wakeup' to analysis perf.data.
>
> Because 'perf record' prefer use 'sched:sched_waking' to
> 'sched:sched_wakeup' since commit d566a9c2d482 ("perf sched: Prefer
> sched_waking event when it exists"). It's very reasonable to
> evaluate process schedule latency.
>
> Similarly, update sched latency/map/replay to use sched_waking events.

Have you checked if it works ok when data has both wakeup and
waking events?

>
> Signed-off-by: Chunxin Zang
> Signed-off-by: Jerry Zhou

Missing email addresses.

Otherwise looks good.

Thanks,
Namhyung


> ---
> tools/perf/builtin-sched.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 86e18575c9be..1af4ec1ac824 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -1819,6 +1819,7 @@ static int perf_sched__read_events(struct perf_sched *sched)
> const struct evsel_str_handler handlers[] = {
> { "sched:sched_switch", process_sched_switch_event, },
> { "sched:sched_stat_runtime", process_sched_runtime_event, },
> + { "sched:sched_waking", process_sched_wakeup_event, },
> { "sched:sched_wakeup", process_sched_wakeup_event, },
> { "sched:sched_wakeup_new", process_sched_wakeup_event, },
> { "sched:sched_migrate_task", process_sched_migrate_task_event, },
> --
> 2.25.1
>
>
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